This invention relates to flexible composite hydraulic hose and more particularly to a wire reinforced hydraulic hose that has a polymeric core tube, an elastomeric cover and a thermal barrier between the core tube and reinforcement which makes the hose particularly suited for high temperature environments.
Hydraulic hose and rigid conduit structures which have fire retardant or fire resistant properties are known in the art. Thus, for example, one form of hose structure comprises a rubber core tube and rubber cover with reinforcement therebetween consisting of a full inner braid of wire, a braided fiberglass sleeve and a loose wire braid. Such structure is relatively large and weighty, lacks a high degree of flexibility and is relatively costly.
Another approach to fire retardant structures is taught in U.S. Pat. No. 4,137,949 wherein carbon cloth inner layers are applied over a conduit and further covered with a glass fiber cloth. The carbon cloth is woven or knitted from carbon fiber and requires a binder to form a matrix for application to a core structure. For flexible cores it is indicated that this binder could be rubber. Two spiral outer layers of woven fiberglass tape are suggested in this structure to complete the composite barrier.
Other flexible hose structures which employ fiberglass reinforcement layers therein over rubber core tubes include U.S. Pat. Nos. 3,500,867 and 4,111,237. In the former, an open weave fiberglass braid is employed in both layers while in the latter, a full or closed weave is preferred.